Recent developments in Vorton Theory

This article provides a concise overview of recent theoretical results concerning the theory of vortons, which are defined to be (centrifugally supported) equilibrium configurations of (current carrying) cosmic string loops. Following a presentation of the results of work on the dynamical evolution of small circular string loops, whose minimum energy states are the simplest examples of vortons, recent order of magnitude estimates of the cosmological density of vortons produced in various kinds of theoretical scenario are briefly summarised.Comment: 6 pages Latex. Contribution to 1996 Cosmology Meeting, Peyresq, Franc

Renormalisation of gravitational self interaction for wiggly strings

It is shown that for any elastic string model with energy density $U$ and tension $T$, the divergent contribution from gravitational self interaction can be allowed for by an action renormalisation proportional to $(U-T)^2$. This formula is applied to the important special case of a bare model of the transonic type (characterised by a constant value of the product $UT$) that represents the macroscopically averaged effect of shortwavelength wiggles on an underlying microscopic model of the Nambu-Goto type (characterised by $U=T$).Comment: 11 pages, Latex; original 8 page version extended to include estimates of relevant orders of magnitude. To be published in Physical Review,

Transonic Elastic Model for Wiggly Goto-Nambu String

The hitherto controversial proposition that a ``wiggly" Goto-Nambu cosmic string can be effectively represented by an elastic string model of exactly transonic type (with energy density $U$ inversely proportional to its tension $T$) is shown to have a firm mathematical basis.Comment: 8 pages, plain TeX, no figure

Winter ozone formation and VOC incremental reactivities in the Upper Green River Basin of Wyoming

The Upper Green River Basin (UGRB) in Wyoming experiences ozone episodes in the winter when the air is relatively stagnant and the ground is covered by snow. A modeling study was carried out to assess relative contributions of oxides of nitrogen (NO_x) and individual volatile organic compounds (VOCs), and nitrous acid (HONO) in winter ozone formation episodes in this region. The conditions of two ozone episodes, one in February 2008 and one in March 2011, were represented using a simplified box model with all pollutants present initially, but with the detailed SAPRC-07 chemical mechanism adapted for the temperature and radiation conditions arising from the high surface albedo of the snow that was present. Sensitivity calculations were conducted to assess effects of varying HONO inputs, ambient VOC speciation, and changing treatments of temperature and lighting conditions. The locations modeled were found to be quite different in VOC speciation and sensitivities to VOC and NO_x emissions, with one site modeled for the 2008 episode being highly NO_x-sensitive and insensitive to VOCs and HONO, and the other 2008 site and both 2011 sites being very sensitive to changes in VOC and HONO inputs. Incremental reactivity scales calculated for VOC-sensitive conditions in the UGRB predict far lower relative contributions of alkanes to ozone formation than in the traditional urban-based MIR scale and that the major contributors to ozone formation were the alkenes and the aromatics, despite their relatively small mass contributions. The reactivity scales are affected by the variable ambient VOC speciation and uncertainties in ambient HONO levels. These box model calculations are useful for indicating general sensitivities and reactivity characteristics of these winter UGRB episodes, but fully three-dimensional models will be required to assess ozone abatement strategies in the UGRB

Poly-essential and general Hyperelastic World (brane) models

This article provides a unified treatment of an extensive category of non-linear classical field models whereby the universe is represented (perhaps as a brane in a higher dimensional background) in terms of a structure of a mathematically convenient type describable as hyperelastic, for which a complete set of equations of motion is provided just by the energy-momentum conservation law. Particular cases include those of a perfect fluid in quintessential backgrounds of various kinds, as well as models of the elastic solid kind that has been proposed to account for cosmic acceleration. It is shown how an appropriately generalised Hadamard operator can be used to construct a symplectic structure that controles the evolution of small perturbations, and that provides a characteristic equation governing the propagation of weak discontinuities of diverse (extrinsic and extrinsic) kinds. The special case of a poly-essential model - the k-essential analogue of an ordinary polytropic fluid - is examined and shown to be well behaved (like the fluid) only if the pressure to density ratio $w$ is positive.Comment: 16 pages Latex, Contrib. to 10th Peyresq Pysics Meeting, June 2005: Micro and Macro Structures of Spacetim

Enclosure resistance in Middlesex, 1656 - 1889: a study of common right assertion

This study provides a detailed examination of resistance to enclosure in Middlesex from the closing stages of the English Republic to the late Victorian period. The evidence presented in the following chapters establishes that resistance was widely spread both over time, (before, during and after any individual enclosure) and geographical location within the county. The study itself is divided into four general sections. The first section is divided into two chapters each having a separate function in setting the scene prior to examining any of the Middlesex evidence. The first chapters sets out both the terminology used by contemporaries and later by historians to describe farming practice in general and the enclosure process in particular. Contemporaries, whether agriculturists or commentators on rural life, and historians have a myriad of terms and conventions to explain the way in which life was organised in the countryside of the past. This introduction to the terminology is necessary. Although I am primarily concerned with labour, and the transition from a rural community with access to the material benefits of common rights to one of exclusive wage dependence, it is still required that we are able to understand the description of agricultural practices as this transition progresses. The second chapter is an examination of previous historians' analysis of enclosure, and their accounts of the responses of commoners to enclosure and the threat of enclosure. The part played by this chapter is to summarise the historical record regarding the commoner as an active player in history or a passive casualty of capitalist improvement. The second section concentrates on the Middlesex rural experience. This is divided into three chapters each dealing with a specific aspect of rural life and work, and acts as a background for the later examination of enclosure resistance. The first of these chapters establishes the agricultural setting of Middlesex throughout the period and assesses the landholding patterns within the county. The second examines how common rights operated locally from parish to parish and from manor to manor. The third chapter shows the use of rights of common in the community and what value was placed on those rights by the commoners themselves. This chapter also surveys the county in order to establish geographically how widespread common rights were in Middlesex. The three following chapters make up the third section and respectively examine the evidence for enclosure resistance between 1656 - 1765; 1766 - 1825 and 1826 - 1889. The reason for this is that each period represents a different era of enclosure. The first era is that of the pre-parliamentary period from 1656 up until 1765. By 'pre-parliamentary' I am referring to local experience. In the sixteenth century the Crown initiated a largely unsuccessful act for the enclosure of Hounslow Heath and this is further discussed in chapter seven. However it was not until 1766 that Middlesex landlords began to use parliament to enclosure their Middlesex estates. Enclosure by personal coercion was a popular device of Middlesex landlords in the seventeenth and eighteenth century and one which they were well prepared to use. Enclosure by act of parliament did not of course remove the coercive element in restricting or extinguishing common rights, however the process was different as was the role of the state; thus the period from 1766 to 1825 has a chapter to itself. This period ends with the 1825 enclosure act for Northolt; the last parliamentary enclosure act for the county. The third chapter deals with the period 1826 to 1889. This final period saw no further individual acts of enclosure although the common fields of several parishes were enclosed under the general enclosure acts of 1836 and 1845, and other commons were enclosed through purchase. Although by this time common rights were severely diminished people were nevertheless willing to fight to keep those rights which had been retained, as well as expressing their dissatisfaction at the loss of previous common rights. The fourth and final section is divided into two chapters. The first examines how the way of life of the commoners was criminalised as the ruling class looked to enclosure as a means of extending their control into every aspect of the lives of those around, (or rather below) them. The purpose of this chapter is to examine how the physical commonfields and commons, and the ideas of common use right and access, interfered with the ability of the local ruling class and their representatives to control the English people. It charts how ideas of crime and anti-social behaviour were attached to the existence of commonlands and how the eradication of the latter would lead to the control of the former. The second chapter of this section examines the evidence in relation to the Marxist interpretation of class struggle and expropriation of the rural peasant. It is also within this chapter that I relate those struggles to the conclusions of earlier historians who have investigated the activity or passivity of the commoners to enclosure. Finally I argue that this struggle was vitally important to class formation, and establishes rural struggles as central to an understanding of class and class consciousness in England during its time as an emerging and maturing capitalist economy. Such conclusions concur with the Marxist view regarding the social and economic condition of commoners and the position of the rural proletariat after enclosure

Coupled currents in cosmic strings

We first examine the microstructure of a cosmic string endowed with two simple Abelian currents. This microstructure depends on two state parameters. We then provide the macroscopic description of such a string and show that it depends on an additional Lorentz-invariant state parameter that relates the two currents. We find that in most of the parameter space, the two-current string is essentially equivalent to the single current-carrying string, i.e., only one field condenses onto the defect. In the regions where two currents are present, we find that as far as stability is concerned, one can approximate the dynamics with good accuracy using an analytic model based on either a logarithmic (on the electric side, i.e., for timelike currents) or a rational (on the magnetic side, i.e., for spacelike currents) worldsheet Lagrangian.Comment: 25 pages, 9 figure

Dynamical Stability of Witten Rings

The dynamical stability of cosmic rings, or vortons, is investigated for the particular equation of state given by the Witten bosonic model. It is found that there exists a finite range of the state parameter for which the vorton states are actually stable against dynamical perturbations. Inclusion of the electromagnetic self action into the equation of state slightly shrinks the stability region but otherwise yields no qualitative difference. If the Witten bosonic model represents a good approximation for more realistic string models, then the cosmological vorton excess problem can only be solved by assuming either that strings are formed at low energy scales or that some quantum instability may develop at a sufficient rate.Comment: 11 pages, LaTeX-ReVTeX (v.3), 2 figures available upon request, DAMTP R-94/1